diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2008-02-09 23:24:09 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2008-02-09 23:24:09 +0100 |
| commit | fac84939609a683503947f41eb93e1917d026263 (patch) | |
| tree | 8bf2df694a2300a277cf097ba778f9b4b28f2122 /arch | |
| parent | x86: cpa, enable CONFIG_DEBUG_PAGEALLOC on 64-bit (diff) | |
| download | linux-fac84939609a683503947f41eb93e1917d026263.tar.xz linux-fac84939609a683503947f41eb93e1917d026263.zip | |
x86: cpa, strict range check in try_preserve_large_page()
Right now, we check only the first 4k page for static required protections.
This does not take overlapping regions into account. So we might end up
setting the wrong permissions/protections for other parts of this large page.
This can be optimized further, but correctness is the important part.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/mm/pageattr.c | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index e5d29a112d00..440210a2277d 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -253,10 +253,10 @@ static int try_preserve_large_page(pte_t *kpte, unsigned long address, struct cpa_data *cpa) { - unsigned long nextpage_addr, numpages, pmask, psize, flags; + unsigned long nextpage_addr, numpages, pmask, psize, flags, addr; pte_t new_pte, old_pte, *tmp; pgprot_t old_prot, new_prot; - int do_split = 1; + int i, do_split = 1; unsigned int level; spin_lock_irqsave(&pgd_lock, flags); @@ -304,6 +304,19 @@ try_preserve_large_page(pte_t *kpte, unsigned long address, new_prot = static_protections(new_prot, address); /* + * We need to check the full range, whether + * static_protection() requires a different pgprot for one of + * the pages in the range we try to preserve: + */ + addr = address + PAGE_SIZE; + for (i = 1; i < cpa->numpages; i++, addr += PAGE_SIZE) { + pgprot_t chk_prot = static_protections(new_prot, addr); + + if (pgprot_val(chk_prot) != pgprot_val(new_prot)) + goto out_unlock; + } + + /* * If there are no changes, return. maxpages has been updated * above: */ |